Pentasa is a brand name for the medication mesalamine (also known as mesalazine or 5-aminosalicylic acid), which is used primarily in the treatment of inflammatory bowel diseases, such as ulcerative colitis and, to a lesser extent, Crohn's disease. It works by reducing inflammation in the colon, helping to control symptoms and prevent flare-ups of the disease. Pentasa is available in various forms, including tablets, capsules, and enemas, allowing for targeted delivery to different parts of the gastrointestinal tract. It is considered an anti-inflammatory agent specifically designed for the digestive tract and is often prescribed as part of a long-term management plan for individuals with chronic conditions.